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include 'proc32.inc'

section '.text' executable

public exp2_ 	as "exp2"

MaskedCW	dw ?

;               We can easily compute 2**int(x) with fscale and

;               2**frac(x) using f2xm1.

exp2_int:

                fstcw   [SaveCW]

                or      byte ptr MaskedCW + 1, 1100b

                fldcw   [MaskedCW]

                fld     st0

                frndint                 ;Compute integer portion.

                fsub    st0, st1    ;Compute fractional part.

                fld1

                faddp    st1, st0	;Compute 2**frac(x).

                fld1                    ;Compute 1*2**int(x).

                fscale

                fstp    st1           ;Remove st(1) (which is 1).

                fstp    st1           ;Remove st1

                ret

;       exp(x) = 2**(x * lg(e))

        fldl2e          ;Put lg(e) onto the stack.

        fmulp st1, st0	;Compute x*lg(e).

        call    exp2_int;Compute 2**(x * lg(e))

        ret

		fld	qword[esp+4]

        call    exp2_int;Compute 2 ** x

        ret